The present invention relates generally to method and apparatus of virtualizing network storage. More particularly the present invention relates to a method and apparatus for virtualizing network storage and permitting access to the network storage separate from virtualization apparatus.
A conventional information processing system stores information in a storage directly connected to a computer system. An access to information stored in the storage is permitted only through the use of the directly connected computer. Accordingly, the other computer systems need to access the data via the directly connected computer. In recent years, the development of network technologies and a dramatic increase in the amount of information to be stored promote separation of a computer system for processing information and a storage system for storing information. Thus, storage can be connected to the network and has become capable of being shared by a plurality of computer systems. Such networked storage is referred to as a network storage.
Examples of such network storage include a storage area network (SAN) storage that is connected by a SAN and provides a block access, a network attached storage (NAS) that is connected for example to an IP network and provides file access, and a Web storage that offers an access according to an interface HTTP protocol or its extended protocol for Web accesses.
As network storages become widely used, a system administrator needs to manage a plurality of network storages connected to the network. When the amount of data to be stored exceeds a maximum value for the existing network storage, for example, it is necessary to add a new network storage and reconfigure the system by re-distributing data or the like. A drastic increase in the need for storage capacities forces repeated system reconfigurations, thus increasing system management costs.
In order to conserve system management costs, a technology for virtualizing storages, specifically consolidating the storage resources as “one big capacity pool” is mandatory so that a plurality of network storages can be viewed as a single storage from the computer system and the entire system is not affected by addition of new devices. Open heterogeneous environments need such technology to manage those resources more efficiently. Various systems have been developed and proposed for virtualizing storages.
However, the conventional configuration of a virtualization box for virtualizing storages is not particularly good being that a customer can not access their data via the host channels for connecting the host to the storage device for other purposes such as reporting, verifying or backing up. In this configuration the customer is required to use one of the ports of the virtualization box.